


Zim’s Greatest Plan

by bh6addict



Category: Invader Zim
Genre: Alien anatomy, Fingering, Inflation, M/M, Male Futanari, Rough Sex, Size Difference, disguises, do Professor Membrane’s arms count as ‘toys’ if he uses them like that?
Language: English
Status: In-Progress
Published: 2019-09-05
Updated: 2019-09-05
Packaged: 2020-10-10 09:36:57
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 3
Words: 8,229
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/20525867
Author URL: https://archiveofourown.org/users/bh6addict/pseuds/bh6addict
Summary: Zim has come up with an AMAZING plan to get Dib out of the picture! All he needs to do is convince Professor Membrane to let him into the house as a parental authority so he can ground the big-headed child! And all that will take is a little... seduction?Set post-ETF





	1. Chapter 1

**Author's Note:**

> So this first chapter or so will be much more plot than smut, but trust me. Smut is my specialty. They’ll get there soon enough

Zim laughed maniacally as he entered the living room, startling the tiny robot on the couch. “Gir! I believe I’ve come up with the ** _mightiest_ ** of plans to eradicate the Dib-smelly!” “ **_You gonna put a big ‘ol ‘splodey thing on the side of his big ‘ol head_**?” Gir lilted. It was definitely the most coherent thing he would have said for the day.

“No Gir… But that would also be a brilliant idea… But what Zim had in mind was more **subtle** !” Zim barked, hands triumphantly finding their way to his hips, “Tell me Gir, what is it that seems to be _ missing _ from the Dib’s house?” Gir gave a sharp hum as his brain wracked to find the best answer. “ _**Aaaah… Oh! I know. It’s- **Oh wait… No I don’t..._” “Isn’t it obvious, Gir! Parental units!” Zim called.

The two barely functioning robots quickly rolled in behind him. Zim motioned to the mom bot, taking a few steps around her for emphasis. “For some reason it seems that Dib doesn’t have a mother figure… This means that it will be easy to trick his father into letting me into their **home-** at which point I can easily ground and spy on that **_filthy_** _big-headed_ human from right inside his own home! It’s **_genius_**!” Zim laughed to himself for a moment as the bots wheeled back off into their closets.

“Yes it’s _ brilliant _ ! All Zim needs is a disguise! **Computer**!” “Yes sir!” The computer dropped a capsule, encasing Zim for a moment before falling open and filling the room with steam. When the steam subsided Zim stepped out of the pod. It really looked like his usual costume just with a longer wig and no pants, but Gir didn’t seem to realize that.

“_ **Ah! Master! There’s a lady in the house! Where did you go!** _ ” “I’m right here, Gir,” Zim lilted as he turned to show off his disguise, “There’s no way the Dib-father can resist me like this! All that’s left is to research how I’m supposed to seduce a _ filthy _ human male.” And with that Zim was off to the lab for his research.

Zim was a little disturbed to say the least when his research led him to human videos of seduction and mating, but when he remembered how tall Professor Membrane was his antennas curled in excitement. It was going to be an honor to be connected to someone that nearly rivaled the height of his tallest.

“Thankfully female human anatomy is quite similar to Irken’s so the Dib-father will not be suspicious when the seduction begins,” Zim explained as he tugged the wig on. Gir gave a low whirring noise as his limbs pulled in to his center. “_**Oooh master! You gonna make babies with Dib’s dad?**_” Zim’s face reddened at that before he scoffed. “Of course not! A dirty human couldn’t get **Zim** pregnant! Besides, there are no eggs in my squeedily spooch,” Zim huffed as he headed out the door.

Phase one of his plan was to get into the Membrane labs and find the professor. Given his knowledge of alien machinery and general science, he figured it would be child’s play in the human labs. If he could impress Professor Membrane then he was sure he would have him as his assistant so the seduction could begin.

It was pretty easy to get into the lab. When the guards didn’t immediately let him in the front door, he was able to just slip into a side door. He did have to search for Professor Membrane though once he was inside, but when he found him it was easy to tell what he was working on.

“What’s this? A miniature particle collider?” Zim hummed as he stepped up to the table that the professor was working at, “Are you planning on making a black hole?” “Hm?” The professor looked up from his work for a moment before shaking his head and quickly returning to it. “No no. It’s going to create a wormhole between my home and the lab. It will make it easier to interact with my darling children!” Professor Membrane responded, typing on the keyboard in front of the machine, “I just can’t seem to get the coordinates right…”

“Let Zim try!” the Irken barked before jumping over to the screen. He analyzed the screen for a moment, raising a brow at the keyboard before tossing it aside. The professor started to protest, but paused when tentacles shot from Zim’s pack and easily connected to the computer. Moments later Zim pulled away as a swirling vortex formed over the collider. “What do you wish to send?” he purred, holding out a tiny gloved hand.

“Hm… To test it we should send something small and firm, yet soft…” Professor Membrane glanced around the lab, but Zim was quick to grab what looked to be a stress ball from the table. “This should be perfect then!” And with no more warning he half-assedly tossed the ball into the vortex.

“Hey! I use that!” Professor Membrane huffed as he went to the desk. “Don’t worry, Professor. If the squish-ball is eviscerated you can grab Zim for relief,” the invader shot back with a devious smirk. Professor Membrane seemed to flush as he gave Zim a confused look, but before he could say anything the ball shot back out and rolled across the floor.

Immediately after the ball returned a screen flew over with Dib’s excited face on it. “You finally got it working, Dad! Oh wow I’m so excited! I can’t wait to- Is that ** _Zim_ **?” The screen turned to the invader, Zim’s eyes widening for a moment before he scoffed. “‘Zim’? Who is this ‘Zim’? I have never met this child in my life!”

“Oh but didn’t you say that was your name earlier? You referred to yourself as ‘Zim’,” Professor Membrane corrected. Zim flushed a bit at that before he shook his head. “Yes well… I-It’s a very common name in Zim’s country. What I meant was that I am not the Zim this child knows,” Zim muttered in explanation as he motioned to Dib.

“Dad that’s the _ alien _! The one that goes to my skool!” Dib huffed. “Oh now don’t be rude, son! Just because she comes from the same country as your little foreign friend doesn’t mean they’re the same person!” the professor scolded. “But dad-!” “No son. We can discuss this later! As for now, I’d like to talk to this brilliant young lady. She’s the one that fixed the collider and I’d like to see what else she could help me with…”

“You won’t get away with this, Zim! I’ll find out what you’re plotting and then I’ll-“ Dib couldn’t even get the rest of his threat out before Professor Membrane ended the transmission. “I’m sorry for his behavior. He’s a little insane at the moment, but I’m sure he’ll grow out of it soon,” the professor explained as he held out his hand, “But thank you for fixing my collider, Zim.”

Zim tilted his head at the outstretched hand before remembering that this was a form of greeting. He quickly took the professor’s hand and shook it vigorously. “It was no trouble at all! Zim is very happy to meet his- I-I mean… her idol! I’ve heard about your work! It is impressive for a silly human.” “Hm?” “I-I mean American! Yes! Impressive for a silly _ American _ ! The technology in my eh… _ country _ is very advanced compared to this…”

After that Professor Membrane had a horde of questions to ask Zim, most of which the invader could easily answer with a lie. Zim made sure to stand as close to the professor as he could without being in the way and he did his best to leave as many lingering touches on his arms and hands as he could. By the time Professor Membrane said he was going to head home Zim had already started making himself comfortable sitting in the professor’s lap, claiming it helped him to better reach the desk. It wasn’t entirely untrue. Zim really did need a sort of booster seat in order to see and reach the top of the desk without standing. That being said, his plan was going more smoothly than he could have ever imagined.


	2. Chapter 2

**Summary for the Chapter:**

> Okay so chapter 2 of... I dunno. We’ll figure that out later. But this is gonna be the first smut chapter! Hope you guys like it!

The next day at Skool Dib was quick to track Zim down before the first bell even rang. “You’ll never get away with whatever you’re planning, Zim! You better leave my dad alone because I’m gonna find out what you’re up to and _ expose _ you!” Dib barked at the invader. Zim gave a wide smirk at that. “I wouldn’t be so sure about that, ** _Dib_ ** . You’ll be calling me _ ‘Mommy’ _ soon enough,” he purred.

“I’ll **never-** ! Wait what? I… Ew… _ Seriously _ Zim what the heck are you up to?” Zim gave a soft huff of laughter. “Oh Dib… Sweet, _ smelly _ , naive little Dib… Isn’t it _ obvious _ ? Your father seems quite interested in my female disguise. Soon he’ll be so _ thoroughly _ seduced that he’ll make me your mother figure! Be prepared for the grounding of a lifetime, ** _Dib_ **!”

Dib’s face turned to a sneer at that, barely able to hold back a gag. “Ew what! You’re trying to ** _date_ ** my dad! That’s too far, Zim! Even for alien _ scum _ like you!” “Oh Zim wasn’t planning on taking all of the unnecessary time for _ dating _. I was going to move straight on to the mating,” Zim responded flatly. Dib’s face lost what little color it had at that. “You’re-... I-... I think I need to go to the nurse… I’m gonna be sick,” Dib grumbled before awkwardly turning and walking off.

For once Dib was left unable to face the invader for the rest of the day. It seemed as if he couldn’t even look at him without having his stomach turn. Zim hadn’t planned this part, but he wasn’t about to complain that the large-headed boy was leaving him alone. It gave him more time to plan his next move.

Once back at his base the first thing he did was go down to the lab to call his Tallest and tell them how smoothly his new plan was going. “Okay _ hold on _ ! Let us get this straight- Your plan… Is to _ seduce _ one of these ** _idiot_ ** humans, **mate** with the _ filthy _ thing, and you just _ hope _ it will make it easier to get this _ one _ child out of the way?” Red scoffed, for once not punctuating his sentence with a long slurp of his drink.

“Oh but sirs this is no _ ordinary _ human! This one is actually rather intelligent. He’s even _ nearly _ as tall as you, my Tallest,” Zim explained. The two Irkens on the screen looked at each other, each face dusted with a blush of his respective color. “Eh… W-Well Zim keep up the good work!” Purple chirped as he turned back to the little invader. “Yeah and uh… Maybe keep us updated while you’re at it,” Red added, his blush darkening just a shade.

Zim nodded, standing at attention. “Yes sirs! I will not disappoint you!” he boomed before scurrying off to begin the next phase of his plan. “So do you think he’s gonna get ripped in half or what?” Red muttered. “Oh uh… Actually I’m kind of hoping he _ doesn’t _ for once. This plan has my squeedily spooch all tingly,” Purple responded awkwardly. “Oh yeah?” Red grinned, glancing back into the empty lab, “Then I guess Zim may actually be _ useful _ for once.” And with that the transmission ended, leaving the lab dark and quiet once again.

“Alright, Gir! Today’s plan is to be _ ‘sensual’ _ with the scientist. Zim will try to be more _ touchy-feely _ with the Dib-father and see if I can get him to return the touchies,” Zim explained. Gir gave an excited little squeal as he hopped up. “ ** _Ooh master’s got a crush!_ ** ” he squawked, bouncing up to him. Zim sneered at that. “No Gir. Zim is not _ crushing _ the Dib-father. Zim is simply _ seducing _ him,” he responded before brushing the little robot out of the way to get to the door.

“Good afternoon _ professor _ ,” Zim purred as he entered the lab. “Ah Zim! Perfect timing!” Membrane boomed, stepping around a large machine to greet the invader, “I’ve tested the collider to see if it would be possible to send a living thing through.” Zim tilted his head a bit at that, but didn’t have time to ask as the professor brought over a tank with several mice and rats. “They all came back _ perfectly _ healthy, so I decided to make a larger collider for easy access between my home and my work.”

“I see…” Zim muttered as he walked around the machine. “Well with a collider this size you’ll want to adjust the speed or else you _ will _ make a black hole,” he corrected as he started tapping at the screen and correcting the scientist’s math, “Not that I think it _ wouldn’t _ be fun to watch you _ struggle _ to keep your lab from getting sucked into an **endless** void, but I’m sure you don’t want that.” “Oh… Well then thank you for fixing that, Zim. I guess it’s a good thing for me that you already know all of this or else my lab would’ve been destroyed.”

“Yes it would,” Zim muttered as he finished up with the machine before turning it on. Another swirling vortex appeared above it and Zim was quick to find the steps that the professor had added onto the machine. “And you can _ thank _ Zim by following me, professor,” the invader hummed as he climbed the steps and easily passed through the hole.

“_ Perfect _ ,” the alien cooed as he stepped out into Professor Membrane’s bedroom. “Zim?” The professor gave a relieved sigh as he stepped out just behind the invader. “Thank _ science _ you’re alright,” he breathed, pressing a hand to his chest, “You should **always** test wormholes before just walking through them! You scared the _ life _ out of me!” Zim gave a low chuckle as he hopped on the bed and crossed his legs, seeming oblivious to the fact that his dress had been hiked up over his hips by the movement.

“Well since your heart is already racing perhaps we could have a little _ fun _?” Zim suggested, reaching out to pull the professor closer to the bed. Professor Membrane easily followed Zim, but once at the bed he simply reached down to adjust his skirt for him, his blush just barely showing over the top of his lab coat. “Maybe instead I could make us some tea. Do you prefer herbal, green, or black?” Membrane diverted before pulling away from the bed and heading for the door.

Zim’s grin quickly fell to a confused pout as he climbed off of the bed and followed the professor to the kitchen. “Eh… Is something _ wrong _ , professor? Is Zim not uh… _ ‘your type’ _ ?” Zim asked, hopping up into a seat at the table as Professor Membrane put a kettle on the stove. The professor blushed a shade or two darker at that before he turned to get them each a mug. “No no… It’s nothing like _ that _ just… How do I put it… It’s just… Well it’s been a _ while _,” Professor Membrane muttered as he prepared the cups.

Zim scoffed as he leaned back in his seat. “That does not matter,” he huffed, “Zim just wishes to be _ connected _ with the professor! I do not care how _ long _ it has been since you last mated.” “I see,” Professor Membrane muttered as he poured them each a cup of black tea and sat across the table from Zim, “You’re _ quite _ an odd little lady, Zim. I like that.” Even though most of his face was covered, Zim could somehow tell that the professor was smiling as he handed him his cup.

“Thanks,” Zim mumbled as he took the cup. He tilted his head a bit when he realized it was hot, but quickly started to enjoy the warm feeling of the mug in his hands. “Maybe we could just _ ease _ into this?” Membrane suggested before taking a sip of his tea, “We could get to know each other a little better first at least.” Zim hid his discontentment by taking a sip of his tea to hide his souring face. “ _ Yes _ or perhaps we could uh… What was it called? When you _ shove _ your faces together _ repeatedly _?”

“You mean _ kiss _ ? I suppose that would be alright,” Professor Membrane agreed, taking one final long sip of his tea before putting the empty cup down, “Would you want to _ now _ ?” Zim perked up at that before quickly nodding. “ _ Yes _ ! Let’s do the kissing thing!” The professor nodded as he stood from his seat. “Then we should go to the bedroom. I’d rather not risk having Dib come in and ruin the moment by getting all _ freaked out _ and _ crazy _ again.”

Zim was quick to follow Professor Membrane to his bedroom, nearly racing him down the hall before flopping down on his bed again. The scientist calmly sat on the edge of the bed and unfastened the top button of his lab coat. Zim wasn’t sure what he expected to be under there, but he was promptly greeted with messy stubble and a soft jawline when the professor adjusted his collar.

“Alright so how do you want to…” Professor Membrane let his sentence trail off as Zim grabbed him by the collar and tugged him down until he was laid back comfortably on the bed with the scientist looming over him. The professor only took a moment to look the invader over before leaning in to press a gentle kiss to his lips. Zim eagerly retuned the kiss, his little arms wrapping around his neck to hold him in place as he opened his mouth to run his tongue over Professor Membrane’s lips.

The professor gave a soft huff at that, hesitant at first to part his own lips, but he slowly relaxed and let him in. Zim was actually surprised by how much he was enjoying this. He was expecting to have to force himself to put up with tasting the professor’s mouth for the sake of the mission, but he was actually enjoying the feeling of their tongues rolling against each other and the taste of tea. He even gave a low moan as one of Professor Membrane’s hands moved to gently slide over his waist.

The professor pulled back a bit at the noise, breaking the kiss to look down at the little alien. “Are you _ sensitive _ , Zim?” he asked as he glanced to the hand that had just barely touched his side. Zim blushed a bit as he tried to pull the professor back in. “What does it matter if I _ am _ ? Zim just wants to keep _ kissing _,” he huffed. The professor grinned a bit at that before leaning back in, but this time instead of kissing his lips he moved down to kiss at his neck.

Zim’s eyes widened at that, having to bite his lip to hold back a soft moan. Professor Membrane gently kissed and sucked at his neck, his mechanical hands moving to carefully grope at his chest. This was another thing Zim wasn’t expecting to enjoy. He had seen humans touching each other’s chests in his research, but he didn’t realize that he could enjoy it even without nipples.

He whimpered softly as he started to feel his cock unsheathe itself before trying to push one of the professor’s hands down to his groin. Professor Membrane finally paused at that as he sat up to look Zim over again. “Perhaps this is going a bit too far,” he muttered, pulling his hands away. Zim gave a needy whine as he sat up. “But professor Zim is _ so _ uh… _ so wet _ for you!” The professor blushed a shade darker as he looked him over. “I suppose it would be a little _ unfair _ to leave you like that when I was the one taking things too far… Let’s just take care of that quickly and then we should call it a day…”

Zim nodded and laid back on the bed again, spreading his legs for the professor. “Sorry if it’s a bit clumsy, darling… My hands aren’t very sensitive. I’ll have to adjust the touch pads later so I can actually _ feel _ what I’m doing next time,” Professor Membrane explained as he brought his hand between the invader’s legs and started carefully sliding a finger over his slit. Zim shuddered at that, reaching up to pull the professor back down to him.

“It’s alright _ professor _. Zim doesn’t mind if it’s not-“ Zim gasped sharply, biting his lip when he felt those fingers start to vibrate against his sex. He gave a needy whine, tilting his head back as the professor rubbed his vibrating digits against the base of his rapidly swelling cock. “Does that feel alright? This isn’t too much, is it?” Zim nodded, biting his lip to hold back a loud moan as his fingers slid down a bit to roll over his entrance.

“Oh ** _Tallest_ ** ! I-It feels **good** professor!” Zim moaned as he arched into the professor’s hand. “Really? Well then let me know when you’ve had enough, Zim,” Professor Membrane breathed as he leaned down to start kissing at his neck again. Zim whimpered, squirming against his fingers as one slowly pressed into him. He was glad that Professor Membrane couldn’t feel it as his palm rested against his cock. He was sure it would give away his alien identity immediately if he noticed that it wasn’t the tiny thing that normally came with female anatomy.

“Professor,” he mewled as that vibrating digit pressed up further into him, gently massaging his inner walls as the professor’s palm brushed against his slick cock. He shuddered when Professor Membrane gave a light nip to his neck. “Oh _ Tallest _ … Professor, Zim is getting _ close _,” Zim whimpered, gripping at the professor’s lab coat. “Oh?” Professor Membrane hummed before pressing his thumb to the base of Zim’s cock.

The little invader couldn’t take it anymore. His fingers dug into the professor’s lab coat, his back arching off of the bed as he tensed around his finger. “** _Professor_ **,” he huffed as he shifted his hips back from his hand. Professor Membrane withdrew his hand, leaning down to press a kiss to the top of Zim’s head as he adjusted his skirt. “Are you satisfied, Zim?”

Zim nodded, bringing his legs together as he felt his length retracting. “Y-Yes… Zim is content with this…” The professor smiled a bit as he started to climb off of the bed. “Alright then I’ll just wash my gloves and we can uh-“ Professor Membrane paused as he looked Zim over, his face going beat-red when he saw a big wet stain on the front of Zim’s dress. “Oh… uh… I didn’t _ realize _ you eh…” He cleared his throat awkwardly and turned to his closet.

“Hm?” Zim raised a brow as he glanced down before quickly matching the professor’s blush and covering himself with his hands. “Ah! I-It’s- This is _ normal _ professor do not worry!” he yelped as he started climbing out of the bed. “Yes Zim I _ understand… _ I was trying to get you something to change into but all of my clothes would be _ far _ too big…” “Z-Zim will just go home for the day! No need to find clothes!” Zim called, already halfway down the hall. “Well at least let me give you a ride h-!” And with a sharp slam of the door Zim was rushing home as inconspicuously as possible.

  
“Gir! Zim needs a ride home ** _now_ ** !” the invader shouted into his communications device. “ ** _Oooh master looks like his plan worked!_ ** ” Zim gave a near growl at that as his face reddened. “Not quite, Gir… Zim was a little distracted this time and ended up splooging all over myself but next time the Dib-father will take me as his mate for sure!” “ ** _Ooh I can’t WAIT to hear about it! It sounds GROSS!_ ** ” the little robot squawked as he pulled up beside his master, “ ** _You’ll have to tell me on the way home!_ **”


	3. Chapter 3

**Summary for the Chapter:**

> okay so it took a while to get this chapter out, but it’s finally here! And shit gets (maybe a little too extra) explicit!

The first thing Zim did when he got back to the base and changed was call his Tallest to update them on his progress. “Ah Zim! What’s the status on your seduction plan?” Red hummed as he saw the little invader. “It is going  _ well _ my Tallest! The Dib-father seems nervous, but he has given me his  _ touchies _ ,” Zim reported. Purple’s antenas perked at that, blushing a bit as he moved closer to the screen. “What exactly do you mean, Zim?” he asked. “Yeah… Tell us  _ in detail _ what happened,” Red purred as he moved up beside Purple.

Zim’s face quickly started turning pink as he gave an award chuckle. “Th-That’s a little  _ personal _ , don’t you think, my Tallest?” he muttered. “Oh  _ come on _ , Zim. It’s not like we’re asking you to show us your schmorple,” Red huffed. “ ** _Yeah_ ** .  _ You _ were the one that called  _ us _ to tell us about your success so why don’t you just  _ tell us _ about it?” Purple agreed, crossing his arms and dropping about half a bag’s worth of chips on the floor.

“I uh… Yes, my Tallest…” Zim took a deep breath before starting his story. He tried to start with some context and then from when he entered the lab, but the Tallest were clearly only interested in the sex. “C’mon Zim just get to the point,” Red groaned. Zim nodded, clearing his throat awkwardly as he averted his eyes. “W-Well Zim did not  _ realize _ that the professor’s fingers could uh…  _ vibrate _ ,” he muttered. He shuddered a bit as he remembered the feeling before continuing.

“We had been smooshing our faces together for a  _ while _ and I didn’t think it would feel so  _ good _ having the human’s tongue in my mouth, but I somehow didn’t hate it…” Zim sighed as he touched his neck. “But then he moved and he was  ** _sucking_ ** on my neck and touching me  _ here _ and I could just feel my schmorple start to swell,” he breathed, moving his hand from his neck to his chest.

The Tallests looked at each other in confusion for a moment before turning back to Zim. “What happened  _ next _ , Zim?” Red hummed, crossing his arms over his chest. Zim bit his lip for a moment, feeling his knees weakening as he thought about what happened next. “Y-Yes… This was when Zim found out that the professor’s fingers could  _ vibrate _ ,” he muttered, looking at anything that wasn’t the screen with the Tallest, “H-He rubbed my schmorple for a few seconds and then his fingers moved down to touch my schmorple  _ hole… _ ”

Purple was biting his lip in anticipation, Red’s antennas curling a bit as Zim continued. “He uh… H-He pushed one of his fingers  _ into _ Zim and was  _ rubbing _ inside…” Zim swallowed down his nerves as he looked up at his leaders. “Sirs, it was like  _ nothing _ Zim had  ** _ever_ ** felt before. I splooged all over my disguise  _ almost _ immediately…”

The Tallests looked at each other for a moment before Red turned back to Zim and cleared his throat awkwardly. “Well Zim…  _ Thank you _ for reporting. We look forward to your  _ next _ report,” he stated, hands resting behind his back. “Yes, my Tallest. I hope to report again soon,” Zim responded. Red nodded back to him before ending the transmission.

Zim let out a breath he hadn’t even realized he’d been holding when the screen went dark again. He glanced around the lab for a moment to see if Gir was scurrying around or playing with anything before he went to his seat. “Computer… I believe I would like to do a bit more  _ research _ on human mating rituals…”

Zim was up very late that night; so late in fact that he was late for Skool that next morning. “Zim. You’re late,” Miss Bitters growled before slinking out from behind her desk, “What’s that on your neck?” She grabbed the little invader by the arm, lifting him to examine him like some sort of rag doll. “Is that a bruise?”

It really didn’t sound like she cared but Zim was quick to cover his neck anyway. “Zim is not bruised! This is simply a freckle!” “Miss Bitters can I go to the nurse? I think I’m going to vomit aga-“ “Dib, you’ve already used all of your nurse’s passes for the year. Just get the bucket,” the teacher hissed before dropping Zim and slithering back behind the desk. Dib grumbled to himself as he crossed the room, shuddering and shaking his head when he looked over to see the dark hickey on the side of Zim’s neck before grabbing the bucket and returning to his desk.

At lunch Dib managed to gather enough nerve to go to Zim’s table. He slammed his hands down to get the invader’s attention, but his face was far less threatening. Zim raised a brow as he looked up from his slop at the pleading face Dib was making at him. “Zim **_please_**! I’ll do whatever you want just _stay_ **_away_** from my dad! I was up **_all night_** after you came over yesterday!”

Zim’s face heated a bit before he gave an awkward chuckle. “You were home?” he squeaked, tugging at the collar on his shirt. “I-I mean-  **Yes** ! I-It is all part of Zim’s  _ genius _ plan! I will keep you up,  _ Dib… _ Night after  ** _night_ ** I will-“ Zim shuddered at the thought, biting his lip before giving a soft sigh. “I will  _ seduce _ the professor… I will feel his fingers playing  ** _deep_ ** inside of my-“

This time he was cut off by Gaz’s hand at his throat. She’d appeared suddenly as if by teleporting at the mention of her father’s sex life. “Zim… One more word about my dad’s fingers and you won’t  _ live _ to see them again,” she growled, gripping just a bit tighter before releasing the alien. Zim coughed a few times before nodding. “You win this time… But  _ soon _ Zim will have  **victory** !” he barked hoarsely before taking his tray and moving across the lunch room.

It was almost two weeks before Zim visited the Membrane labs again, but when he finally showed up Professor Membrane was ready with the warmest of greetings.

“Oh Zim… Welcome back. I’m happy to see you,” he said softly, seeming surprised to see the little invader. Zim gave an awkward smile as he went to the professor’s seat and started to climb up onto his lap. “What are you working on today, professor?” he asked. When he felt metallic hands wrap around his waist and lift him, he was a little confused and very shocked, but he was quickly placed on the back of the chair to be out of the professor’s way.

“I’ve been making adjustments to my sensors… I wasn’t really sure if you would be coming back after you left in such a rush, but I figured it would be best to be able to feel things properly anyway. It’s just been taking a while only being able to work with and  _ on _ one arm at a time,” Professor Membrane explained as he rested one arm on the table and used the other to start tinkering with it. Zim blushed a bit at that, resting his own arms and chin on top of the professor’s head as he watched. “I see… Eh… Z-Zim- I… am sorry for not coming back,” he murmured.

The professor let out a soft huff of a chuckle. “It’s alright, darling,” he assured, “I’m just happy to see your pretty face again.” Zim’s blush only darkened as his fingers started mindlessly brushing through Professor Membrane’s hair. “You’re a very nice man, aren’t you professor?” Zim muttered against his scalp. The professor shrugged at that. “I suppose I try…”

Zim gave a thoughtful hum as he sat up a bit. “How far along are your sensors?” Professor Membrane raised the hand he was working on, presenting it to the invader. “Try touching my palm,” he suggested, not looking at his hand. Zim looked at it for a moment before pressing his hand to his palm. After a couple of seconds Professor Membrane gently closed his fingers around his hand and looked over.

“I think it’s still delaying, but I can feel more clearly now,” the professor stated before putting his hand back down on the table, “just a  _ little _ more and they should be at  **peak** condition buy tomorrow afternoon.” Zim nodded, continuing to watch for a moment before he gave a little hum. “How far along do you think they would be  _ tonight _ ?”

Professor Membrane paused at the tone of Zim’s voice. “My my… Aren’t you impatient,” he chuckled as he went back to his work, “I think I can get the reaction time a  _ bit _ better, but I may still need to watch what I’m doing to get the full experience.” Zim shuddered at the thought of having the professor’s hands on him again. “Yes professor… Zim believes that will be fine…”

Zim watched as Professor Membrane continued to work on his hands, growing increasingly impatient as the minutes passed. He perked up when he finally saw him adding a bit of silicone padding over the wires in his fingers and palms. “Is that it professor?” the little invader asked excitedly. Professor Membrane chuckled as he shook his head. “I still have to get my arms, darling,” he hummed, opening a panel on his arm to start working. Zim gave a slight pout at that, but slowly started to grin as he leaned in by Professor Membrane’s ear.

“Professor, Zim cannot wait to feel your big, thick fingers in hi-er uh- her sloppy cunt,” the alien breathed in the scientist’s ear. Professor Membrane shuddered at that. “You really do know how to turn a man on, Zim,” he boomed before pulling the little green creature onto his lap, “I suppose my sensors are close enough to being finished if you’re really that desperate.”

Zim’s eyes widened as he was lifted off of the back of the chair and into the professor’s lap, but he quickly remembered all of his ‘research’ and did his best to relax and remember what he was supposed to say next. “Y-Yes professor! I wish to feel you  _ deep _ inside!  _ Scrambling _ my  **delicate** insides with your uh… Y-Your cock?” Zim only vaguely remembered the anatomy, but the professor didn’t seem to mind.

Professor Membrane gave a low chuckle as his hands slid down Zim’s hips until they could slip back up his thighs under his dress. Zim shuddered at that, gently gripping at the professor’s lab coat. “For such a naughty girl you sure seem sensitive… Are you scared, Zim?” Membrane hummed, thumb just barely tracing up the slit of Zim’s sex. The alien let out a low whimper but quickly shook his head.

“Z-Zim fears nothing! Especially not the hands of such a handsome scientist,” Zim lilted, biting his lip as he hesitantly pressed his hips forward. “How bold, Zim,” Professor Membrane chuckled before gently spreading him open with his first and ring finger, his middle finger rolling over his slowly slickening sex. Zim gave an audible gasp at that, but decided to bite his tongue as that thick finger pressed into him.

“It’s already so warm and wet, Zim. Were you really so excited?” Membrane purred as he lifted the bottom of his dress with his free hand to watch as his finger carefully slipped in and out of the slick hole. “Hm?” He raised a brow when he saw something pink starting to poke out from between the invader’s slit. “Isn’t your clitoris swelling up an awful lot?”

Zim whimpered, hands trembling as he tried to hide his rapidly growing erection. “I-It’s perfectly normal! Please don’t look!” Professor Membrane chuckled softly as he moved Zim’s hands out of the way. “There’s no need to be embarrassed, Zim! In fact, would you mind letting me suck it for you? I think it’s  _ amazing _ how big it’s getting.”

Zim could feel his antennas curl excitedly under his wig as he nodded. “Z-Zim believes that will be fine,” he muttered. “Fantastic,” the professor breathed, pushing aside his work before lifting Zim onto the desk and pulling his seat up. “Could you spread your legs for me a bit, darling?” Zim nodded, knees trembling as he spread his legs for the professor.

Professor Membrane wasted no time slipping his finger back into the little alien as he tugged his lab coat down and brought his lips to his swelling cock. As soon as those lips brushed his burning erection Zim couldn’t hold back a low moan. “P-Professor,” he mewled as those lips wrapped around him and easily took him in to the hilt. The professor gave a low groan of his own around him as he started to suck and move his head.

The more he sucked, the larger Zim’s ‘clit’ seemed to swell into his mouth. Professor Membrane didn’t mind at all though. He easily took the growing cock into his throat a few times before pulling off to examine it in amazement. “Astonishing… It’s the size of a grown man’s penis,” he breathed, glancing up at Zim and admiring the pleasured look on his face. “Darling, your clit is nearly big enough for the tip to touch your stomach. Honestly, it’s  _ disturbingly _ erotic,” he hummed before going back down on him.

Zim moaned desperately as the professor took him back into his throat, his eyes widening as he felt him carefully pushing in a second metallic finger. “A-Ah P-Professor!” he whimpered as his legs tensed and held his head. Professor Membrane just moaned against his sex as he slowly pumped his fingers in and out of the alien, gently curving them as Zim laid back on the desk.

Zim’s thin fingers all but clawed at Professor Membrane’s scalp as he spread him open and hummed against his cock. “P-Professor I- Oh my  ** _Tallest_ ** !” he huffed, toes curling in his boots as those metal fingers started to vibrate and shove forcefully into him. Zim tilted his head back, his wig falling out of place as he tensed around those fingers and spilled his irken seed down the professor’s throat.

Professor Membrane didn’t stop at that though. He kept moving his fingers deep inside the tight opening as he slipped off of the twitching cock. Zim was a mess on the desk as he shuddered and tried to pull his legs together. “P-Professor please,” he panted, “Z-Zim has had  _ enough _ for now… My uh… My p-pussy is  _ so _ sensitive.” “Oh but darling that means it’s the best time to play with it,” Professor Membrane hummed, gently tugging off the askew wig.

Zim whimpered as he shakily tried to reach for the wig, but his body felt too heavy to fight as the professor tossed it out of his reach. “It’s alright, Zim. You don’t have to be embarrassed about that. I think you’re just as amazing without it,” the scientist cooed as he leaned in to kiss the top of his green head. Zim huffed as he shifted his hips against the still moving fingers, watching as Professor Membrane started unbuttoning his lab coat.

He had to bite his lip to suppress a low moan when he felt himself tighten around his fingers again. He couldn’t help it. Seeing how large the bulge in the professor’s pants was just sent him over the edge again. He was both excited and terrified to see the cock of such a tall creature.

“You really are excited, aren’t you Zim? Did you have another orgasm just from seeing me start to undress?” Professor Membrane teased, spreading his fingers a bit before slipping them out to unbuckle his belt. “I-It’s because your fingers feel so good, professor,” Zim panted.

The professor grinned slightly as he tugged his pants down just enough to release his thick cock. Zim’s eyes widened as he looked at it, his knees trembling. “Oh my tallest,” he breathed, gasping as Professor Membrane grabbed his legs and spread them apart. “How much of me do you think you can take, Zim? You’re so small. Will the tip even fit?”

Zim shuddered as Professor Membrane rolled his cock against his sex, teasing the sensitive hole. “Why don’t you put it in and find out?” he huffed as he gave the professor his most devious grin. “I think I’m really enjoying this experiment,” Professor Membrane purred before finally lining himself up and slowly pushing in.

Zim had never been more grateful for his durability in his life as the professor’s cock stretched his inner walls. A human his size would have broken the moment it went in, but he was able to lie back and feel as Professor Membrane pushed deeper and deeper into him. When he stopped pushing, Zim gave a needy whine.

“W-Why did you stop? Zim wishes to be  _ connected _ !” “Zim I don’t want to  _ actually _ break anything. I would hate it if I ruptured one of your internal organs with my penis… Besides-“ His hand brushed over Zim’s midsection, making the alien shudder as he looked down at his hand. He gave a low whine when he saw that his skin was stretched into a thick lump right where the head of the professor’s cock would be.

“Th-This is  ** _nothing_ ** ! Do not worry professor! I promise this is  _ normal _ ! Please just give it all to me. Zim is  _ yours _ for the taking!” Of course he only meant physically and only in this moment. Zim would absolutely never put a human above his tallest. Even if he was the smartest of the humans. And very tall. And incredibly generous, surprisingly kind… “ _ Please _ professor… I wish to feel you  _ pounding _ into every part of my body. I’m much stronger than you think.”

“Well… I suppose we have the technology to fix anything that may break if you’re really sure…” Zim’s eyes lit up at that as he nodded desperately. “ **Yes** !  _ Please _ professor!” he begged, gripping at his coat. Professor Membrane nodded at that before leaning down to press a gentle kiss to the alien’s lips.

The kiss did little to distract Zim as he felt the professor push the last few inches of his cock into him. When his hips finally pressed against him Zim bit down on the professor’s lip. “That’s all of it, Zim,” Professor Membrane breathed as he sat up to look down at him, “let me know when you want me to move…”

Zim gave a needy whine as he shifted his hips. “Y-You can move  _ now _ ! Oh  ** _Tallest_ ** ! I can feel you in my squeedily spooch already,” Zim huffed, head leaning back against the desk. The professor was hesitant to move at first but slowly started to rock his hips in and out of the small alien. Zim groaned blissfully as the scientist moved inside of him, rolling his own hips to try to get even more friction.

“P-Professor please… Zim wants you to move  ** _faster_ ** !” he mewled desperately as the professor’s hands slid down his sides before gripping his hips. “Don’t push yourself, Zim… This is already way too much for such a little lady,” Professor Membrane huffed, but he wasn’t about to ignore Zim as his gentle rocking quickly picked up to full thrusts. Zim cried out at that, his hands moving to grip those mechanical wrists.

“Oh _my_ **_Tallest_**! Oh yes _professor_! Zim is feeling so **good**!” The alien was panting to catch his breath as each thrust shoved his squeedily spooch into his chest. His little hands scrambled to find something to hold on to before finally gripping his slicked cock. He pumped himself a few times before he felt those cold and metallic fingers brush his own hands out of the way.

He let out a needy cry when Professor Membrane gripped his cock and started stroking him with his thrusts which were quickly growing more and more rough. Zim’s hands moved instead to just grip the desk as the professor used his free hand to pull his small body down into him like some sort of cocksleeve. “Y-Yes professor!  _ Use _ Zim’s body as you please! Oh  _ Tallest _ I can feel it  _ filling _ my squeedily spooch!” Zim cried as he finally tensed around Professor Membrane’s cock, a thick pink liquid spilling over his hand as he came.

The professor groaned and started to pull out of the tight hole, but Zim whimpered and tried his best to wrap his feet around his hips to pull him back in. “No professor!  ** _Please_ ** ! Zim- I-I want to feel you  _ fill _ my squeedily spooch with your huma-  _ A-American _ ejaculate! Please just use me to finish as  _ quickly _ as you can,” Zim panted, looking up at the professor with pleading eyes.

“Is this some sort of kink? Do you  _ enjoy _ being used like this?” Membrane asked as he lifted the little invader off of the desk and started repeatedly pulling him down onto his cock. Zim had to move his hands to cover his mouth and contain another desperate cry, but he nodded in response as Professor Membrane sat back down in his chair. “Well then I suppose I’ll play along…”

After that the professor was quick to start pumping Zim over his cock, just jerking him up and down as the alien mewled and tensed around him. “H-Harder professor…  _ Please _ hurry and fill Zim,” the invader begged as he gripped the hands that held him. Professor Membrane nodded, pausing for just a moment to press a light kiss to the top of his head before he started forcefully pulling him down onto his cock.

Zim whined desperately as the professor started thrusting up into him as he shoved him down his length. “I’m almost there, darling… Just a  _ little _ more…” The alien whimpered as the professor stood back up, now slamming his hips forward as he tugged him down to meet him. It only took a few thrusts like this before Professor Membrane finally held Zim tight against his hips, still jerking forward a few times as he filled Zim with his thick seed.

He held him there for a moment before he slowly pulled him back off. Zim gave a low whine when he finally felt the professor’s cock slip out of his beaten hole. “P-Professor,” he panted, holding his arms out toward him. He’d seen the humans cling to each other after mating in several of his research videos and he thought it looked quite comfortable. The professor smiled as he sat down and gently held the alien to his chest.

Zim gave a content sigh as he rested his head on Professor Membrane’s chest, his antennas relaxing back against his head as one of his mechanical hands carefully brushed over his back. “Are you satisfied, Zim?” Professor Membrane asked after a few moments. Zim nodded, not looking up at the professor as he gripped his shirt. “Zim is more than just satisfied, professor. This… It was more than Zim ever expected.”

“I’m glad… And you’re feeling alright? Nothing out of place in there?” Zim sat up a bit at that, his hands pressing around his body before he shook his head. “Zim is fine.” Professor Membrane gave a soft chuckle at that, not realizing Zim was actually feeling around for his organs and not just trying to be cute. “Fantastic. And what about cleaning up? Would you like me to lend you a hand?”

Zim blushed a bit at that. The humans ‘cleaned up’ in several of the videos he watched and he wasn’t sure he was ready to go again. “What do you mean when you say ‘ _ lend a hand _ ’ professor?” he asked warily. “Well…” The professor gave a low hum as he carefully lifted Zim back onto the desk and spread his legs, watching for a moment as his seed slowly leaked out of him.

“I could lick you clean if you’d like,” he purred, giving Zim a slight smirk. Zim shuddered at that before glancing down at his cock which was finally almost completely sheathed once again. “A-Alright… Just don’t touch my uh… My…” He couldn’t remember what the professor thought it was so instead he just motioned to the dime-sized tip that was still poking out. “Zim is very sensitive after  _ so much _ playing…”

Professor Membrane nodded before leaning in and sliding his tongue over the messy hole. Zim shuddered as he laid back on the desk and just enjoyed the gentle feeling of the professor’s tongue rolling around and into him. It only lasted a few moments and only turned the invader on enough for his cock to swell an inch or so before the professor pulled back off. Professor Membrane hummed softly as he adjusted Zim’s skirt for him and stood back up for a moment to adjust his own clothes, leaving his coat hanging open.

Zim was quick to crawl back into the professor’s lap when he sat back down. He felt exhausted and frankly he enjoyed the warmth of the professor’s chest. He just cuddled back up to him, clinging to the scientist as he rapidly fell asleep.


End file.
